The CDC Cyber 205
The Cyber 205 system had its origins in the STAR-100 computer
[1].
The STAR-100 resulted from a line of development at CDC separate from
that which lead from that which led to the Cray-1. This started in
1965 in response to a requirement of the Lawrence Livermore Laboratory
for a vector processor capable of executing 100 MFLOPS. A great deal
of controversy raged about this machine in its early years, and many
of the essential design issues and performance goals have been
obscured
[2].
Despite the many difficulties
which arose in the course of the STAR-100 programme, CDC remained
convinced that the underlying architectural concepts of the STAR-100
were sound, and went on to produce a second version, the STAR-100A,
which appeared commercially as the CYBER 203, and a further, completely
re-engineered version, the STAR-100C, which was produced
commercially as the CYBER 205. In 1983 CDC formed a spin-off company,
ETA Systems Inc., with the goal of producing a multiprocessor system
(the ETA 10), based on the CYBER 205 architecture and having a
performance capability of 10 GigaFLOPS. A small number of these
systems were sold commercially before the company closed down.
The STAR-100 was criticised on a number of grounds by users who wished
to apply it to more general computing problems than those for which it
was designed. The grounds for criticism were mainly the long vector
start-up time and poor performance on scalar arithmetic, both of which
were inevitable consequences of the design. These problems are largely
overcome in the CYBER 205
[3]
by the use of a
very much faster (80 ns access time) semiconductor memory and by the
inclusion of a high performance scalar unit. The overall performance
of the CYBER 205 was further enhanced by its implementation in
specially developed ECL LSI Uncommitted Logic Array technology,
allowing a reduction of the clock period from the 40 ns used in the
STAR-100 to 20 ns.